Added ZfcUser integration

Solves issue #1.

View when the user is signed in :
![rbcomment_zfc_user_1](https://f.cloud.github.com/assets/507871/1860913/56d56c14-77ba-11e3-8ffa-fa0f0ff28bf8.png)

View when the user is not signed in :
![rbcomment_zfc_user_2](https://f.cloud.github.com/assets/507871/1860918/5edb14fe-77ba-11e3-89f7-6499eb5b5573.png)